• 1.

    Ahmed S, et al.. Examining the potential impact of race multiplier utilization in estimated glomerular filtration rate calculation on African-American care outcomes. J Gen Intern Med [published online ahead of print October 15, 2020]. doi: 10.1007/s11606-020-06280-5

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  • 2.

    Diao JA, et al.. Clinical implications of removing race from estimates of kidney function (Research Letter). JAMA [published online ahead of print]. doi: 10.1001/jama.2020.22124

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  • 3.

    Norris KC, et al.. Removal of race from estimates of kidney function: first, do no harm (editorial). JAMA [published online ahead of print]. doi: 10.1001/jama.2020.23373

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Dropping eGFR Race Factor Would Increase CKD Diagnoses in Black Patients

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Dropping the use of the race coefficient in estimating the glomerular filtration rate (GFR) from serum creatinine would significantly increase the number of Black patients diagnosed with chronic kidney disease and result in about one-third of CKD patients being reclassified to a more severe stage, according to a pair of recent studies.

“Both papers try to estimate the impact of removing the race multiplier in terms of how many patients would be impacted by a reclassification in CKD stage,” said Mallika Mendu, MD, MBA, assistant professor at Harvard Medical School and co-author of a study published in the October Journal of General Internal Medicine (JGIM). Although the two studies looked at different population datasets, the findings “very much aligned.”

The studies are designed to provide data to inform the debate as the use of a race coefficient for Black patients in GFR estimation has come under increasing scrutiny. Many institutions have dropped the use of the coefficients.

In August 2020, ASN and the National Kidney Foundation formed a joint task force (ASN-NKF) to focus on the use of race in the GFR estimation. The task force plans to issue an interim report in January and a final report in the spring.

“The task force has been receiving expert testimony and assessing the scientific literature, including newly published articles like these. It is now deliberating to meet its charge to ensure that GFR estimation equations provide an unbiased assessment of kidney function,” said Tod Ibrahim, ASN Executive Vice President. “ASN and NKF are committed to reversing the racial health inequities in the United States through efforts that address both health disparities and social determinants of health.”

Both studies examined the impact of the race modifier in computing eGFR from serum creatinine using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). The CKD-EPI equation modifier increases eGFR for Blacks by nearly 16%.

The JGIM study, co-authored by Ahmed et al. (1), looked at a CKD registry at two large academic medical centers. A research letter online on Dec. 2, 2020, in the Journal of the American Medical Association (JAMA), by Diao et al. (2), used data from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional sample of the U.S. population, during 2001–2018.

The JGIM study found: “Of 2225 African American patients, 743 (33.4%) would hypothetically be reclassified to a more severe CKD stage if the race multiplier were removed from the CKD-EPI equation. Similarly, 167 of 687 (24.3%) would be reclassified from stage 3B to stage 4.” Some 64 of 2069 patients (3.1%) would have their eGFR moved below the 20 mL/min/1.73 m2 criterion for being added to the transplant list.

The JAMA research letter found that in its sample of 9522 Black adults, the removal of race would result in a median decrease in eGFR of 14.1 mL/min/1.73 m2. “Removing race may increase the prevalence of CKD among Black adults from 14.9% to 18.4%. Concurrently, 29.1% of Black adults with existing CKD may be reclassified to more severe stages of disease, with significant clinical and pharmacological implications,” the authors write. And although the reclassification would make more patients eligible to receive a transplant, it would also disqualify more people from being eligible to donate a kidney.

In an editorial accompanying the research letter, Norris et al. (3) state that extrapolating this 14.9% to 18.4% increase in prevalence “could possibly indicate an estimated 1 million Black adults having a new diagnosis of CKD.”

Mendu, who is a member of the ASN-NKF task force, said she was surprised at the size of the effects: “The argument we have heard from many is that this isn’t a big deal and it is not really going to affect many people whether we use [the race multiplier] or don’t use it. What both papers show is that it is affecting a lot of the patients it is being applied to, so it can’t be ignored.”

According to the JAMA research letter, “Removal of race adjustment may increase CKD diagnoses among Black adults and enhance access to specialist care, medical nutrition therapy, kidney disease education, and kidney transplantation, while potentially excluding kidney donors and prompting drug contraindications or dose reductions for individuals reclassified to advanced stages of CKD.”

The accompanying editorial notes that reclassifying patients to CKD stage 4 would make “patients no longer eligible for certain treatments (e.g., metformin and sodium glucose transporter-2 inhibitors)” and would thus involve a trade-off between “the potential benefits of significantly slowing CKD progression among potentially a million or more individuals vs. the loss of treatment among a much smaller group of individuals in the late stages of disease (who might inevitably progress toward kidney failure).”

The JAMA research letter notes: “This potential for benefits and harms must be interpreted in light of persistent disparities in care, documented biases of eGFR without race, and the historical misuse of race as a biological variable to further racism.”

Neil R. Powe, MD, MPH, MBA, a co-author of the JAMA letter, said a careful examination of the data in the articles indicates that healthcare “disparities are driven by other factors than the equation and that the equation has become a scapegoat. We need to concentrate on the real drivers of disparities to make change.”

Powe is professor of medicine at the University of California, San Francisco, and co-chair of the ASN-NKF task force on race and GFR estimation.

“Clinicians must recognize that regardless of race, eGFR is an imprecise measure at the patient level,” the JGIM authors note. “The risk of underestimation versus overestimation must be recognized and mitigated by the use of biomarkers such as cystatin C that can estimate GFR without the use of race.” They add, “many African-Americans face the challenge of more rapid acceleration to ESRD compared with other racial groups, so on average, they would likely benefit from earlier counseling and preparation for renal replacement therapy as well as earlier nephrology and transplant referral.”

The ASN-NKF task force is hosting online forums to solicit input: Jan. 15, 6–8 p.m. ET, focused on input from clinicians, scientists, and other health professionals; and Jan. 22, 6–8 p.m. ET, focused on patients, family members, and other public stakeholders.

References

  • 1.

    Ahmed S, et al.. Examining the potential impact of race multiplier utilization in estimated glomerular filtration rate calculation on African-American care outcomes. J Gen Intern Med [published online ahead of print October 15, 2020]. doi: 10.1007/s11606-020-06280-5

    • Search Google Scholar
    • Export Citation
  • 2.

    Diao JA, et al.. Clinical implications of removing race from estimates of kidney function (Research Letter). JAMA [published online ahead of print]. doi: 10.1001/jama.2020.22124

    • Search Google Scholar
    • Export Citation
  • 3.

    Norris KC, et al.. Removal of race from estimates of kidney function: first, do no harm (editorial). JAMA [published online ahead of print]. doi: 10.1001/jama.2020.23373

    • Search Google Scholar
    • Export Citation
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